Mask having multiple transmittances

ABSTRACT

A mask including a transparent substrate, a non-transmitting layer, a first transmitting layer and a second transmitting layer is provided. The transparent substrate has a first region, a second region, and a third region. The non-transmitting layer is disposed in the first region of the transparent substrate. The first transmitting layer is disposed in the second region and the third region of the transparent substrate. The second transmitting layer is disposed on the first transmitting layer in the third region.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of and claims the priority benefit ofpatent application Ser. No. 11/444,546, filed on May, 31, 2006, whichclaims the priority benefit of Taiwan application serial no. 94131047,filed on Sep. 9, 2005. The entirety of the above-mentioned patentapplications is hereby incorporated by reference herein and made a partof this specification.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a mask and a manufacturing methodthereof. More particularly, the present invention relates to a phaseshift (halftone) mask (PSM) and a manufacturing method thereof.

2. Description of Related Art

Generally, the manufacturing process of a conventional mask includes thefollowing steps. First, a quartz substrate whereon a metal layer hasbeen formed is provided. A photoresist layer is formed on the quartzsubstrate and the metal layer, and by exposing and developing in certainareas, part of the photoresist layer is removed to expose the metallayer thereunder. Next, the exposed metal layer is removed through a dryetching process or wet etching process. Thus, non-transmitting andtransmitting patterns are formed on the quartz substrate after thephotoresist layer is removed completely. Finally, a transparent pellicleis formed over the substrate, so a binary mask is completed.

Even though the binary mask is widely used in the industry, but slittype mask is generally used upon the reduction of the devicesmanufacture process. But slit type mask will bring in diffractioneffect, which may affect the exposure evenness of the photoresist.Accordingly, there will be unnecessary pattern residue after etching.

A phase shift (halftone) mask can resolve both low accuracy and unevenexposure problems. However, the general manufacturing method for phaseshift (halftone) mask is identical to the method for manufacturing abinary mask. First a binary mask is manufactured. After that, a phaseshift (halftone) thin film is formed on the binary mask, then aphotoresist layer is formed on the mask and the phase shift (halftone)thin film, and then by exposing and developing in certain areas, part ofthe photoresist layer is removed to expose the phase shift (halftone)thin film thereunder. After that, the exposed phase shift (halftone)thin film is removed through a dry etching process or wet etchingprocess. After the photoresist layer is completely removed, atransparent pellicle is formed, thus a phase shift (halftone) mask isfinished. Note that the transmittance of phase shift (halftone) thinfilm depends on the film material, film thickness, and phase angle.

Even though the phase shift (halftone) mask can resolve the problems oflow accuracy and uneven exposure, as etching technology is used in themanufacturing method thereof, when uneven etching occurs on the phaseshift (halftone) thin film, the thickness of the phase shift (halftone)thin film on the mask will be uneven. Accordingly the transmittance orphase angles may be different after the light passes through the phaseshift (halftone) thin film at different locations of the mask so as tolead to low yield in the lithography process.

Moreover, the manufacturing process of the phase shift (halftone) maskis as follows: forming a layer of phase shift (halftone) thin film on abinary mask after the binary mask is initially formed; performing alithography process to define the pattern of the phase shift (halftone)thin film; then transferring the pattern to the phase shift (halftone)thin film through an etching process; finally removing the photoresistcompletely. Compared to the conventional binary mask, there may be moredefects when manufacturing the mask due to the complicated manufacturingprocedure. Accordingly, the manufacturing cost thereof may be increased.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a mask manufacturingmethod, wherein the phase shift (halftone) layer is fabricated through alift-off process to avoid uneven thin film thickness due to an etchingprocess.

The present invention is also directed to a mask manufacturing methodcapable of reducing the manufacturing cost of the phase shift (halftone)mask.

According to yet another aspect of the present invention, a mask isprovided, wherein the mask has never appeared in the conventional mask.

The present invention provides a mask manufacturing method, includingthe following steps. First, a transparent substrate having a firstregion, a second region, and a third region is provided. Then, anon-transmitting layer is formed in the first region of the transparentsubstrate. After that, a first photoresist layer is formed on thetransparent substrate and exposes the second region of the transparentsubstrate. Next, a first transmitting layer is formed on the transparentsubstrate and the first photoresist layer. The first photoresist layeris removed, wherein the first transmitting layer located on the firstphotoresist layer is removed at the same time, the first transmittinglayer formed in the second region of the transparent substrate isremained, and the third region of the transparent substrate is exposed.

According to an embodiment of the present invention, the transparentsubstrate further includes a fourth region, and after the step ofremoving the first photoresist layer, the method further includes thefollowing steps. A second photoresist layer is formed on the transparentsubstrate and exposes the fourth region of the transparent substrate. Asecond transmitting layer is formed on the transparent substrate and thesecond photoresist layer. The second photoresist layer is removed,wherein the second transmitting layer located on the second photoresistlayer is removed at the same time and the second transmitting layerformed in the fourth region of the transparent substrate is remained. Inan embodiment, the material of the first transmitting layer is differentfrom that of the second transmitting layer. In another embodiment, thethickness of the first transmitting layer is different from thethickness of the second transmitting layer. In yet another embodiment,both the material and the thickness of the first transmitting layer aredifferent from those of the second transmitting layer.

According to an embodiment of the present invention, the firsttransmitting layer and the second transmitting layer described above arephase shift (halftone) thin films respectively. In addition, the phaseshift (halftone) thin film comprises, for example, metal silicide, metalfluoride, metal silicide oxide, metal silicide nitride, metal silicideoxynitride, metal silicide carbide oxide, metal silicide carbidenitride, metal silicide carbide oxynitride, alloy, thin metal film,carbide, carbon oxide, or a combination thereof.

The present invention also provides a method for remanufacturing a mask,which includes the following steps. First, a mask having a first region,a second region, and a third region is provided, wherein anon-transmitting layer has been formed in the first region, and the maskis covered by a pellicle. After the pellicle covering the mask isremoved, a first photoresist layer is formed on the mask and exposes thesecond region of the transparent substrate. After that, a firsttransmitting layer is formed on the transparent substrate and the firstphotoresist layer. The first photoresist layer is removed, wherein thefirst transmitting layer located on the first photoresist layer isremoved at the same time, the first transmitting layer formed in thesecond region of the transparent substrate is remained and the thirdregion of the transparent substrate is exposed.

According to an embodiment of the present invention, the mask furtherincludes a fourth region, and after the step of removing the firstphotoresist layer, a second photoresist layer is formed on the mask andexposes the fourth region of the mask. After that, a second transmittinglayer is formed on the mask and the second photoresist layer. The secondphotoresist layer is removed, wherein the second transmitting layerlocated on the second photoresist layer is removed at the same time andthe second transmitting layer formed in the fourth region of the mask isremained. In an embodiment, the material of the first transmitting layeris different from that of the second transmitting layer. In anotherembodiment, the thickness of the first transmitting layer is differentfrom that of the second transmitting layer. In yet another embodiment,both the material and the thickness of the first transmitting layer aredifferent from those of the second transmitting layer.

The present invention provides another mask manufacturing method, whichincludes the following steps. First, a transparent substrate having afirst region, a second region, and a third region is provided. Anon-transmitting layer is formed in the first region of the transparentsubstrate. A first photoresist layer is formed on the transparentsubstrate and exposes the second region and the third region of thetransparent substrate. A first transmitting layer is formed on thetransparent substrate and the first photoresist layer. The firstphotoresist layer is removed, wherein the first transmitting layerlocated on the first photoresist layer is removed at the same time, thefirst transmitting layer formed in the second and the third regions ofthe transparent substrate is remained. A second photoresist layer isformed on the transparent substrate, which covers the non-transmittinglayer and the first transmitting layer in the second region and exposesthe first transmitting layer in the third region. After that, a secondtransmitting layer is formed on the second photoresist layer to coverthe exposed first transmitting layer. The second photoresist layer isremoved, wherein the second transmitting layer located on the secondphotoresist layer is removed at the same time and the secondtransmitting layer formed on the first transmitting layer in the thirdregion is remained. In an embodiment, the material of the firsttransmitting layer is different from that of the second transmittinglayer. In another embodiment, the thickness of the first transmittinglayer is different from that of the second transmitting layer. In yetanother embodiment, both the material and the thickness of the firsttransmitting layer are different from those of the second transmittinglayer.

According to an embodiment of the present invention, the aforementionedtransparent substrate further includes a fourth region, and in the stepof forming the first photoresist layer, the transparent substrate in thefourth region is exposed. In addition, after the step of removing thefirst photoresist layer, the first transmitting layer is remained in thefourth region. In the step of forming the second photoresist layer, thefourth region is covered. After the step of removing the secondphotoresist layer, the first transmitting layer in the fourth region isexposed. Subsequently, a third photoresist layer is formed on thetransparent substrate and exposes the first transmitting layer in thefourth region. Next, a third transmitting layer is formed on the thirdphotoresist layer to cover the first transmitting layer in the fourthregion. After that, the third photoresist layer is removed, wherein thethird transmitting layer located on the third photoresist layer isremoved at the same time and the third transmitting layer formed on thefirst transmitting layer in the fourth region is remained.

The present invention further provides a mask including a transparentsubstrate, a non-transmitting layer, a first transmitting layer, and asecond transmitting layer. The transparent substrate includes at least afirst region, a second region, and a third region, the non-transmittinglayer is located in the first region of the transparent substrate, thefirst transmitting layer is located in the second region of thetransparent substrate, and the second transmitting layer is located inthe third region of the transparent substrate. In particular, the secondregion is adjacent to the third region, such that the first transmittinglayer is adjacent to the second transmitting layer.

In an embodiment, the thickness of the first transmitting layer isdifferent from that of the second transmitting layer. In anotherembodiment, the material of the first transmitting layer is differentfrom that of the second transmitting layer. In yet another embodiment,both the material and the thickness of the first transmitting layer aredifferent from those of the second transmitting layer.

As described above, compared to the conventional technology, the presentinvention can avoid uneven thickness induced by an etching process byusing a lift-off process in the manufacturing process of transmittinglayers. Moreover, according to the present invention, halftone patternsof various transmittance can be formed on the mask by formingtransmitting layers of different thicknesses, or different materials, orboth different thicknesses and different materials. If the phase shift(halftone) thin film is used in the transmitting layers, then the maskformed is halftone phase shift (halftone) mask, which has the advantagesof simpler manufacturing process and lower manufacturing cost comparedto the conventional phase shift (halftone) mask.

In order to make the aforementioned and other objects, features andadvantages of the present invention comprehensible, a preferredembodiment accompanied with figures is described in detail below.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIGS. 1A to 1F are cross-section views illustrating a mask manufacturingmethod according to the first embodiment of the present invention.

FIGS. 2A to 2E are cross-section views illustrating another maskmanufacturing method according to the first embodiment of the presentinvention.

FIGS. 3A to 3F are cross-section views illustrating a mask manufacturingmethod according to the second embodiment of the present invention.

FIGS. 4A to 4D are cross-section views illustrating another maskmanufacturing method according to the second embodiment of the presentinvention.

FIGS. 5A to 5H are cross-section views illustrating a mask manufacturingmethod according to the third embodiment of the present invention.

FIGS. 6A to 6K are cross-section views illustrating another maskmanufacturing method according to the third embodiment of the presentinvention.

FIG. 7 is a cross-section view of a mask according to an embodiment ofthe present invention.

DESCRIPTION OF EMBODIMENTS

FIGS. 1A to 1F are cross-section views illustrating a mask manufacturingmethod according to the first embodiment of the present invention. Themask manufacturing method of the present embodiment includes thefollowing steps. Referring to FIG. 1A, first, a transparent substrate110 having a first region 120, a second region 130, and a third region140 is provided. The transparent substrate 110 is, for example, a quartzsubstrate or transparent substrate of other materials. Then, anon-transmitting layer 150 is formed on the substrate, which is, forexample, chromium film of 700 to 2000 angstroms in thickness combinedwith chromium oxide film of 100 to 300 angstroms in thickness,preferably chromium film of 800 to 1200 angstroms in thickness combinedwith chromium oxide film of 100 to 200 angstroms in thickness. Othermaterials which can be used in the non-transmitting layer 150 arecarbide, carbon oxide, or stable black resin.

Referring to FIG. 1B, a patterning process is performed to thenon-transmitting layer 150 to form a non-transmitting layer 150 a. Thepatterning process includes a lithography process and etching process,wherein the lithography process is, for example, by defining photoresistwith laser or e-beam, and the etching process is, for example, a dryetching or wet etching process.

Referring to FIG. 1C, a first photoresist layer 160 is coated over theentire substrate. Next, a lithography process is performed to the firstphotoresist layer 160 to form a first photoresist layer 160 a, whichexposes the second region 130 of the transparent substrate 110, as shownin FIG. 1D. The lithography process is, for example, to expose withlaser or e-beam. The corresponding device areas of the exposed secondregion 130 are, for example, channel region of TFT, Cs contact region ofauxiliary capacitor, reflective region of transflective type orreflective type LCD, organic layer of multi cell gap, photo spacer,multi domain vertical alignment (MVA), protrusion of color filter,critical layer of semiconductor which needs high resolution, forexample, a gate layer, contact layer, or other layers.

Referring to FIG. 1E, next, a first transmitting layer 170 is formed onthe substrate 110 and the first photoresist layer 160 a, wherein theformation method is, for example, a low temperature collimatedsputtering or chemical vapor deposition process with field screen. Here,the first transmitting layer 170 has higher transmittance relative tothe non-transmitting layer 150. In an embodiment, the material of thefirst transmitting layer 170 is, for example, a phase shift (halftone)thin film, the material of the phase shift (halftone) thin filmcomprises, for example, metal silicide, metal fluoride, metal silicideoxide, metal silicide nitride, metal silicide oxynitride, metal silicidecarbide oxide, metal silicide carbide nitride, metal silicide carbideoxynitride, alloy, thin metal film, carbide, carbon oxide, or thecombinations thereof, wherein the metals which can be combined include,for example, molybdenum, tantalum, zirconium, chromium, and tungstenetc.

Referring to FIG. 1F, a lift-off process is performed to remove thefirst photoresist layer 160 a. Meanwhile, the first transmitting layer170 located on the photoresist layer 160 a is removed together, thefirst transmitting layer 170 a in the second region 130 is remained andthe third region 140 of the transparent substrate 110 is exposed. Ahalftone mask 100 having transmitting pattern, non-transmitting pattern,and halftone pattern is completed through the aforementioned process. Ifphase shift (halftone) thin film is used in the first transmitting layer170, then the completed mask is halftone phase shift mask (HTPSM).

FIGS. 2A to 2E are cross-section views illustrating another maskmanufacturing method according to the first embodiment of the presentinvention, which is modified from the mask manufacturing method shown inFIGS. 1A to 1F. Referring to FIG. 2A, the halftone mask 102 in FIG. 2Aincludes a transparent substrate 110, a non-transmitting layer 150 a,and a first transmitting layer 170 a, wherein the transparent substrate110 includes a first region 120, a second region 130, a third region140, and a fourth region 210. The non-transmitting layer 150 a islocated in the first region 120, and the first transmitting layer 170 ais located in the second region 130. The non-transmitting layer 150 aand the first transmitting layer 170 a are the same as or similar tothose described in the aforementioned embodiment so are not explainedagain.

Referring to FIG. 2B, a second photoresist layer 220 is coated over thetransparent substrate 110. Next a lithography process is performed tothe second photoresist layer 220 to form a second photoresist layer 220a, which exposes the fourth region 210 of the transparent substrate 110,as shown in FIG. 2C. The lithography process is the same as or similarto the one described in the aforementioned embodiment, and thecorresponding device area of the exposed fourth region 210 is one ofthose device areas mentioned above.

Referring to FIG. 2D, next, a second transmitting layer 230 is formed onthe transparent substrate 110 and the second photoresist layer 220.Here, the second transmitting layer 230 has higher transmittancerelative to the non-transmitting layer 150 a, and the transmittance ofthe first transmitting layer 170 is different from the transmittance ofthe second transmitting layer 230. In an embodiment, the thickness ofthe first transmitting layer 170 is different from that of the secondtransmitting layer 230. In another embodiment, the material of the firsttransmitting layer 170 is different from that of the second transmittinglayer 230. In yet another embodiment, both the material and thethickness of the first transmitting layer 170 are different from thoseof the second transmitting layer 230. The material of the secondtransmitting layer 230 is, for example, a phase shift (halftone) thinfilm.

Next, a lift-off process is performed to remove the second photoresistlayer 220 a. Meanwhile, the second transmitting layer 230 on the secondphotoresist layer 220 a is removed together and the second transmittinglayer 230 a in the fourth region 210 is removed, as shown in FIG. 2E.Thus the manufacturing process of the multi-tone mask 200 is completed.If the phase shift (halftone) thin film is used in the aforementionedfirst transmitting layer 170 and second transmitting layer 230, then thecompleted mask 200 is multi-tone phase shift (halftone) mask (MTPSM).

Note that to have the best result, the thicknesses of the photoresistand the phase shift (halftone) thin film are controlled to avoid peelingwhen the lift off process is performed in the present embodiment. Thisrequirement can be met by coating thicker photoresist and using a lowtemperature collimated sputtering process, or by using a chemical vapordeposition process with field screen. Moreover, increasing developertemperature and adding in vibration, for example, mega sonic vibration,when exposing can remove the thin film on the photoresist completely,and pollution can be prevented by the changing and controlling ofdeveloper.

FIGS. 3A to 3F are cross-section views illustrating a mask manufacturingmethod according to the second embodiment of the present invention,which includes the following steps.

Referring to FIG. 3A, first, a recycled mask having a transparentsubstrate 110, a non-transmitting layer 150 a, and a pellicle 310 isprovided. The transparent substrate 110 includes a first region 120, asecond region 130, and a third region 140, and the non-transmittinglayer 150 a is located in the first region 120.

Referring to FIG. 3B, the pellicle 310 is removed to expose thenon-transmitting layer 150 a and the transparent substrate 110 coveredby the pellicle 310.

Referring to FIG. 3C, a first photoresist layer 320 is coated over theentire substrate 110. Next, a lithography process is performed to thefirst photoresist layer 320 to form the first photoresist layer 320 a,as shown in FIG. 3D, to expose the transparent substrate 110 in thesecond region 130.

Referring to FIG. 3E, next, a first transmitting layer 330 is formed onthe transparent substrate 110 and the first photoresist layer 320 a. Thefabricating method and material used are the same as or similar to thoseof the first transmitting layer 170 described in the first embodiment.

After that, a lift-off process is performed to remove the firstphotoresist layer 320 a, and the first transmitting layer 330 located onthe photoresist layer 320 a is removed together, and the firsttransmitting layer 330 a in the second region 130 is remained, as shownin FIG. 3F. Thus a halftone mask 300 is completed. Similarly, if phaseshift (halftone) thin film is used in the first transmitting layer 330,then the completed mask is halftone phase shift (halftone) mask.

FIGS. 4A to 4D are cross-section views illustrating another maskmanufacturing method according to the second embodiment of the presentinvention, which is modified from the mask manufacturing methodillustrated in FIG. 3A to 3F. Referring to FIG. 4A, the halftone mask302 includes a transparent substrate 110, a non-transmitting layer 150a, and a transmitting layer 330 a. The transparent substrate 110includes a first region 120, a second region 130, a third region 140,and a fourth region 210. The non-transmitting layer 150 a is located inthe first region 120, and the first transmitting layer 330 a is locatedin the second region 130.

Referring to FIG. 4B, a second photoresist layer (not shown) is coatedover the transparent substrate 110. After that, a lithography process isperformed to the second photoresist layer to form the second photoresistlayer 340 a, which exposes the transparent substrate 110 in the fourthregion 210.

Referring to FIG. 4C, next, a second transmitting layer 350 is formed onthe transparent substrate 110 and the second photoresist layer 340 a.The fabricating method and material used are the same as or similar tothose of the first transmitting layer 170 described in the firstembodiment. In an embodiment, the thickness of the first transmittinglayer 330 is different from the thickness of the second transmittinglayer 350. In another embodiment, the material of the first transmittinglayer 330 is different from the material of the second transmittinglayer 350. In yet another embodiment, both the material and thethickness of the first transmitting layer 330 are different from thoseof the second transmitting layer 350.

Next, a lift-off process is performed to remove the second photoresistlayer 340 a. The second transmitting layer 350 located on the secondphotoresist layer 340 a is removed at the same time and the secondtransmitting layer 350 a in the fourth region 210 is remained, as shownin FIG. 4D. So a multi-tone mask 400 is completed through the processdescribed above. Similarly, if phase shift (halftone) thin film is usedin the first transmitting layer 330 and the second transmitting layer350, then the completed mask is multi-tone phase shift (halftone) mask.

By using this embodiment, those masks which have been used on theproduction line can be recycled and reprocessed, so that cost can bereduced considerably, and the five mask manufacturing processes in thearray manufacturing of TFT LCD can be combined into four or threeprocesses. Accordingly, the manufacturing cost of large size mask can bereduced and the production capacity of photolithography can beincreased.

FIGS. 5A to 5H are cross-section views illustrating a mask manufacturingmethod according to the third embodiment of the present invention, whichincludes the following steps. Referring to FIG. 5A, first, a transparentsubstrate 110 having a first region 120, a second region 130, and athird region 140 is provided. The transparent substrate 110 is, forexample, a quartz substrate or transparent substrate of other materials.A non-transmitting layer 150 is then formed on the transparent substrate110. The thickness and material of the non-transmitting layer 150 arethe same as or similar to those described in the first embodiment.

Referring to FIG. 5B, a patterning process is performed to thenon-transmitting layer 150 to form a non-transmitting layer 150 a. Thepatterning process is, for example, a lithography process or etchingprocess, and the lithography process is, for example, by defining thephotoresist with laser or e-beam, and the etching process is, forexample, a dry etching or wet etching process.

Referring to FIG. 5C, next, a first photoresist layer (not shown) iscoated over the entire substrate 110. After that a lithography processis performed to the first photoresist layer to form a first photoresistlayer 510 a, which exposes the second region 130 and the third region140 of the transparent substrate 110. The lithography process is thesame as, for example, the one described in the first embodiment, and thecorresponding device area of the exposed two regions is one of thosedevice areas described above.

Referring to FIG. 5D, next, a first transmitting layer 520 is formed onthe transparent substrate 110 and the first photoresist layer 510 a. Thefabricating method and material used are the same as or similar to thoseof the first transmitting layer 170 described in the first embodiment.

A lift-off process is performed to remove the first photoresist layer510 a. The first transmitting layer 520 on the first photoresist layer510 a is removed at the same time and the first transmitting layer 520 ain the second region 130 and the third region 140 is remained, as shownin FIG. 5E.

Next, referring to FIG. 5F, a second photoresist layer (not shown) iscoated over the transparent substrate 110. Next a lithography process isperformed to the second photoresist layer to form the second photoresistlayer 530 a, which exposes the first transmitting layer 520 a in thethird region 140 of the transparent substrate 110.

Referring to FIG. 5G, next, a second transmitting layer 540 is formed onthe transparent substrate 110 and the second photoresist layer 530 a.The fabricating method and material used are the same as or similar tothose of the first transmitting layer 170 described in the firstembodiment.

Next, a lift-off process is performed to remove the second photoresistlayer 530 a. The second transmitting layer 540 located on the secondphotoresist layer 530 a is removed at the same time and the secondtransmitting layer 540 a on the first transmitting layer 520 a in thethird region 140 is remained, as shown in FIG. 5H. In an embodiment, thethickness of the first transmitting layer 520 is different from that ofthe second transmitting layer 540. In another embodiment, the materialof the first transmitting layer 520 is different from that of the secondtransmitting layer 540. In yet another embodiment, both the material andthe thickness of the first transmitting layer 520 are different fromthose of the second transmitting layer 540. A multi-tone mask 500 iscompleted through the process described above. Similarly, if the phaseshift (halftone) thin film is used in the first transmitting layer 520and the second transmitting layer 540, then the completed mask ismulti-tone phase shift (halftone) mask.

FIGS. 6A to 6K are cross-section views illustrating another maskmanufacturing method according to the third embodiment of the presentinvention, which is modified from the mask manufacturing methodillustrated in FIGS. 5A to 5H. Referring to FIG. 6A, a transparentsubstrate 110 having a first region 120, a second region 130, a thirdregion 140, and a fourth region 210 is provided. Then, anon-transmitting layer 150 is formed on the transparent substrate 110.

Referring to FIG. 6B, a patterning process is performed to thenon-transmitting layer 150 to form a non-transmitting layer 150 a. Thepatterning process is, for example, a lithography process or etchingprocess, wherein the lithography process is, for example, by definingthe photoresist with laser or e-beam, and the etching process is, forexample, a dry etching or wet etching process.

Referring to FIG. 6C, next, a first photoresist layer (not shown) iscoated over the transparent substrate 110. Next, a lithography processis performed to the first photoresist layer to form a first photoresistlayer 610 a, which exposes the second region 130, the third region 140,and the fourth region 210 of the transparent substrate 110.

Referring to FIG. 6D, next, a first transmitting layer 620 is formed onthe transparent substrate 110 and the first photoresist layer 610 a. Thefabricating method and material used are the same as those of the firsttransmitting layer 170 described in the first embodiment.

After that, a lift-off process is performed to remove the firstphotoresist layer 610 a. The first transmitting layer 620 located on thefirst photoresist layer 610 a is removed at the same time and the firsttransmitting layer 620 a in the second region 130, the third region 140,and the fourth region 210 is remained, as shown in FIG. 6E.

Referring to FIG. 6F, next, a second photoresist layer (not shown) iscoated over the transparent substrate 110. After that, a lithographyprocess is performed to the second photoresist layer to form a secondphotoresist layer 630 a, which exposes the first transmitting layer 620a in the third region 140 of the transparent substrate 110.

Referring to FIG. 6G, next, a second transmitting layer 640 is formed onthe transparent substrate 110 and the second photoresist layer 630 a.The fabricating method and material used are the same as or similar tothose of the first transmitting layer 170 described in the firstembodiment.

After that, a lift-off process is performed to remove the secondphotoresist layer 630 a. The second transmitting layer 640 located onthe second photoresist layer 630 a is removed at the same time and thesecond transmitting layer 640 a on the first transmitting layer 620 a inthe third region 140 is remained, as shown in FIG. 6H.

Referring to FIG. 6I, next, a third photoresist layer (not shown) iscoated over the transparent substrate 110. After that, a lithographyprocess is performed to the third photoresist layer to form a thirdphotoresist layer 650 a, which exposes the first transmitting layer 620a in the fourth region 210 of the transparent substrate 110.

Referring to FIG. 6J, next, a third transmitting layer 660 is formed onthe transparent substrate 110 and the third photoresist layer 650 a. Thefabricating method and material used are the same as or similar to thoseof the first transmitting layer 170 described in the first embodiment.

After that, a lift-off process is performed to remove the thirdphotoresist layer 650 a. The second transmitting layer 660 located onthe third photoresist layer 650 a is removed at the same time and thethird transmitting layer 660 a on the first transmitting layer 620 a inthe fourth region 210 is remained, as shown in FIG. 6K. A multi-tonemask 600 is completed through the process described above. If a phaseshift (halftone) thin film is used in the first transmitting layer 620,the second transmitting layer 640, and the third transmitting layer 660,then the completed mask is multi-tone phase shift (halftone) mask.

FIG. 7 is a cross-section view of a multi-tone mask manufacturedaccording to the embodiments of the present invention described above.Referring to FIG. 7, the multi-tone mask 700 includes a transparentsubstrate 1 10, a non-transmitting layer 150, a first transmitting layer720, and a second transmitting layer 740. The transparent substrate 110includes a first region 120, a second region 130, and a third region140. The non-transmitting layer 150 is located in the first region 120,the first transmitting layer 720 is located in the second region 130,and the second transmitting layer 740 is located in the third region140. In particular, the second region 130 is adjacent to the thirdregion 140 such that the first transmitting layer 720 is adjacent to thesecond transmitting layer 740, which has different transmittance.

In an embodiment, the thickness of the first transmitting layer 720 isdifferent from that of the second transmitting layer 740. In anotherembodiment, the material of the first transmitting layer 720 isdifferent from that of the second transmitting layer 740. In yet anotherembodiment, both the material and the thickness of the firsttransmitting layer 720 are different from those of the secondtransmitting layer 740.

The mask of the present invention can be used not only in themanufacturing process of LCD devices, but also in the manufacturingprocess of reflective board in reflective type TFT LCDs or transflectivetype TFT LCDs. Moreover, the mask of the present invention can also beused in any step coverage pattern design or taper angle pattern design.

In summary, the mask and the manufacturing method thereof in the presentinvention have at least the following advantages:

-   -   a) The lift-off method is used in the mask manufacturing method        of the present invention to simplify the manufacturing procedure        of phase shift (halftone) mask and to reduce defects.        Accordingly, the manufacturing cost of phase shift (halftone)        mask can be reduced.    -   b) Compared to the manufacturing method of conventional phase        shift (halftone) mask, which removes part of the phase shift        (halftone) thin film through an etching process, the mask        manufacturing method of the present invention uses a lift-off        method to avoid uneven thickness of the phase shift (halftone)        thin film incurred by uneven etching, so that phase shift        (halftone) mask with even transmittance and even phase angle can        be manufactured when the thickness of the phase shift (halftone)        thin film is controlled, and the yield of the production line        process can be improved.    -   c) The mask manufacturing method of the present invention can        remanufacture phase shift (halftone) mask using recycled        conventional binary mask, which not only reduces the        manufacturing cost of phase shift (halftone) mask considerably,        but also combines the five mask manufacturing processes in the        array production line of TFT LCD into four or three processes,        further improving the yield of the lithography process.    -   d) In the present invention, a simple mask manufacturing        procedure of HTPSM and MTPSM is exposed, which can be used        widely in the photolithography process of displays, color        filters, and semiconductors to reduce the process steps of TFT        LCD array, lower the manufacturing cost, improve the shape of        photoresist, and further improve the evenness of the panel and        reduce the mura without adding extra equipment.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1. A mask, comprising: a transparent substrate with a first region, asecond region, and a third region; a non-transmitting layer disposed inthe first region of the transparent substrate; a first transmittinglayer disposed in the second region and the third region of thetransparent substrate; and a second transmitting layer disposed on thefirst transmitting layer in the third region.
 2. The mask of claim 1,wherein the material of the first transmitting layer is different fromthe material of the second transmitting layer.
 3. The mask of claim 1,wherein the thickness of the first transmitting layer is different fromthe thickness of the second transmitting layer.
 4. The mask of claim 1,wherein both the material and the thickness of the first transmittinglayer are different from those of the second transmitting layer.
 5. Themask of claim 1, wherein the transparent substrate further includes afourth region, the first transmitting layer is further disposed in thefourth region of the transparent substrate, and a third transmittinglayer is disposed on the first transmitting layer in the fourth region.6. The mask of claim 5, wherein the material of the first transmittinglayer is different from the material of the second transmitting layer.7. The mask of claim 5, wherein the thickness of the first transmittinglayer is different from the thickness of the second transmitting layer.8. The mask of claim 5, wherein both the material and the thickness ofthe first transmitting layer are different from those of the secondtransmitting layer.
 9. The mask of claim 5, wherein the material of thethird transmitting layer is different from the material of the secondtransmitting layer.
 10. The mask of claim 5, wherein the thickness ofthe third transmitting layer is different from the thickness of thesecond transmitting layer.
 11. The mask of claim 5, wherein both thematerial and the thickness of the third transmitting layer are differentfrom those of the second transmitting layer.